1. Field of the Invention
The present invention relates, in general, to vacuum breakers and, more specifically, to vacuum breakers for use in a flush valve assembly.
2. Description of Related Art
Vacuum breakers are currently used in water supply systems where there is danger of back-syphonage occurring from contaminated plumbing fixtures such as urinals and toilets to enter back into the potable water supply feeding a flush valve. For example, U.S. Pat. No. 3,334,646 to Billeter et al. discloses a vacuum breaker having a substantially cylindrical elastomeric body with a plurality of cylindrically-spaced ends positioned about a lower portion of the body. An upper portion of the body includes a recess to receive a tapered baffle or insert member having a plurality of water ports.
U.S. Pat. No. 5,564,460 to Gronwick et al. also discloses a vacuum breaker that includes a substantially cylindrical elastomeric body with a plurality of circumferentially-spaced projections positioned about a lower portion of the body. The body further includes a tapered inner surface positioned below the projections. A baffle is received within a recess defined at an upper portion of the body.
Finally, U.S. Pat. No. 6,189,554 to Pino discloses a vacuum breaker for a flush valve that includes a flexible sleeve having a plurality of projections circumferentially spaced about the outer surface of the body and a tapered lip seal positioned below the projections. A baffle is received by a recess defined in the body at an upper portion thereof. U.S. Pat. Nos. 3,334,646; 5,564,460 and 6,189,554 are hereby incorporated by reference.
FIG. 1 illustrates one type of prior art vacuum breaker assembly 10, similar to those disclosed in the above-referenced patents. The prior art vacuum breaker assembly 10 includes an outlet tube 12 having circumferentially-spaced air openings 14. A coupling nut 16 is used to attach the vacuum breaker assembly 10 to a lower section 18 of a flush valve 20 (partially shown). A typical flush valve is described in U.S. Pat. No. 5,271,600, assigned to Zurn Industries, Inc., which is hereby incorporated by reference. A downstream end of the outlet tube 12 is adapted to connect to an inlet side of a water closet or urinal (not shown).
Referring to FIGS. 1 and 2, the prior art vacuum breaker assembly 10 includes a prior art vacuum breaker 22 having a substantially cylindrical body 23 positioned inside of the outlet tube 12. The vacuum breaker 22 having a first end 24 and a second end 26 is suitably formed of a rubber-like or flexible elastomeric material. The first end 24 of the vacuum breaker 22 includes a flange 28 having a double-sided recess 30 for receiving an outwardly extending flange 32 of a cone-shaped flow control insert 34 or baffle arrangement. The insert 34 includes a plurality of openings for the passage of water. A paper gasket seal 38 is typically seated on top of the flange 28 to seal the first end 24 of the vacuum breaker 22 to a lower section 18 of the flush valve 20. A shield 40 attached to a lower end of the coupling nut 16 is spaced from air openings 14 so that the air openings 14 may perform their intended function of admitting air at atmospheric pressure into an interior of vacuum breaker assembly 10 to prevent back-syphonage.
FIG. 2, which shows a bottom view of the prior art vacuum breaker 22, includes a plurality of lip seals 42, 44 and 46 at the second end 26 of the body 23 of the vacuum breaker 22. Each of these lip seals 42, 44 and 46 has circumferentially-spaced projections or ribs 48 which are slightly thicker than other portions of the lip seals, with the ribs 48 defining between them a slit 50 which can open to permit the passage of water through the vacuum breaker assembly 10.
The prior art vacuum breaker 22 performs in the following manner. In normal use, the flow of water into the vacuum breaker assembly 10 will pass through the cone-shaped flow control insert 34, with water pressure forcing the lip seals 42, 44 and 46 to spread apart, permitting water to flow through slits 50 to a plumbing fixture connected at an outlet end of the vacuum breaker assembly 10 (not shown). In the event that there is a negative pressure at a water supply, air will flow in through air openings 14. This causes the walls of vacuum breaker 22 to collapse, preventing the passage of water from the downstream plumbing fixture into the potable water supply. The purpose of the vacuum breaker 22 is to expand during every flush to prevent weeping (i.e., water leakage) and contract after the flush is done to allow pressure equalization. In operation, vacuum breaker 22 will rapidly expand outwardly against the interior wall of outlet tube 12 to seal air openings 14 and prevent water leakage.
The prior art vacuum breakers discussed above suffer from various drawbacks. First, each of the designs discussed above requires a double-sided recess 30 adapted to receive an insert 34 or baffle arrangement, thus making installation of the insert 34 or baffle arrangement difficult to install. Furthermore, the typical cone-shaped insert 34 or baffle arrangement used in prior art vacuum breakers creates a relatively high pressure drop. Finally, the plurality of projections or ribs 48 defining slits 50 therein of the prior art vacuum breaker 22 are often prone to tearing or other similar durability problems when receiving water at high pressure.
Accordingly, a need exists for a vacuum breaker that allows for simple installation of a flow control insert or baffle arrangement. A further need exists for a vacuum breaker with high durability that includes a flow control insert or baffle arrangement that leads to a reduced pressure drop.